Balloon Demonstration
Key Concepts to Emphasize:
- Galaxies aren’t flying through space like rockets; space is growing between them.
- The Big Bang wasn’t an explosion in space, but an expansion of space.
Materials:
- A balloon (preferably a large, round one)
- A permanent marker/or Sharpie
Prepare the Balloon:
- Before inflating, draw several small dots around the surface of the deflated balloon.
- These dots represent galaxies scattered throughout the universe.
- Explain: “Each dot is a galaxy — a huge group of stars like our Milky Way. The balloon itself is space.”
- Show the balloon fully deflated and scrunched up.
- Say: “At the very beginning — the Big Bang — everything was squeezed into a tiny space, like this scrunched-up balloon.”
- Slowly blow air into the balloon, letting it expand while watching the dots get farther apart.
- Ask your learner to observe what’s happening.
- If they don’t, point out how every dot seems to move away from every other dot, no matter where you look on the balloon.
- “As space expands, all the galaxies move away from each other, just like the dots on this balloon move apart as it gets bigger.”
- “No matter which galaxy you stand on, it looks like all the other galaxies are moving away from you. That’s because space itself is stretching.”
- “What does this tell us about the nature of space and the universe?”
- “If the balloon keeps getting bigger, what might happen to the galaxies in the future?”